LAUBE: This is Hai el Becker, it's a neighborhood of the city of Hit, a very ancient city in Iraq. There is talk of Hit being where the ark was constructed. Legendary type stuff like that.

PALMER: But most of these Marines are more concerned with surviving day-to-day than with learning the history of Hit.

Threats to these Marines come from every direction and in many forms.

Marines never know when they'll walk into a neighborhood where hidden gunmen are determined to kill them.

This sniper attack was a hasty affair: the shooter fires a few rounds, and then he disappears.

But the greatest danger by far to Marines and to civilians is the ubiquitous IED, the improvised explosive device.

ANKRUM: They just found a, what they call a daisy-chained IED, is where they connect each individual artillery round together so when they initiate the explosion, all four blow at one time. They had two 152mm rounds and two 122mm rounds, you know, casualty radius on one of those rounds is, like, a 100 meters. That's a pretty big explosion. If a vehicle was rolling by that and it went off, it would take out the whole vehicle easily.

After the troops find a bomb, they blow it up.

BROUSSARD: I don't have that dumb, "I'm gonna live forever" feeling or mentality like I had last year, you know?

PALMER: This is Lance Corporal Damon Broussard's second Iraq deployment.

BROUSSARD: That year was like, riding up in the turret, IEDs blowing up all over and still not caring. This year, you know, I'm about to get married, you know, got a little more to look forward to. I kinda ride a little lower in the turret, you know, make sure I don't give them that once chance to keep me from going home this time.

PALMER: It's Washington's policy to transfer the bulk of fighting from U.S. troops to Iraqi forces like these, but that's barely started to happen here.

These Iraqi soldiers aren't trained or equipped well enough to operate without U.S. forces. And there's no police force in Hit. That means these young Marines are the law.

Remember the sniper attack?

After the gunfire died down, the Marines rounded up a half dozen men. Suspects.

These two men were working in a welding shop nearby.

The Marines tested each man for gunpowder residue; there's not a trace on any them, so they are being released.

It's another uncomfortable moment for these Iraqi men as they wait for the Marines to return their ID cards and dismiss them. They're free to go, but they've been shamed in their own neighborhood, their powerlessness displayed publicly.

The Marines enter Iraqi homes without warrants to search for anything they consider threatening or suspicious...

What at first seems a threat often isn't...

This man had a single weapon in his home. He was allowed to keep it under a regulation that permits each household to have one rifle for self-defense.

At another house, Marines and Iraqi soldiers find neatly wrapped bags of gunpowder. They tie the owner's hands and question him through a translator.

His story? He uses the gunpowder to fish, a dangerous but not uncommon method of angling in Iraq. The Marines release him.

When Marines do find something suspicious  hidden weapons or ammunition  they round up the nearest military-aged males, or "mams" in Marine-speak, for questioning.

This man and his young son were fishing just as Marines unearthed a pile of weapons yards away. Both were detained and then released.

While the Marines suffer from a shortage of reliable intelligence, enemy forces often know when they're coming.

But today they didn't. The Marines moved under cover of rain.

The BLT's Bravo company surprised a group of armed men in a farmhouse outside of Hit during an operation called "smokewagon."

BOBADILLA: I ran about 5 meters, had to get to the staff sergeant, rounds coming behind. I heard them too. That was the scariest moment of my life.

PALMER: The Marines say one man had live explosives strapped to his chest.

They killed three of the men in a short firefight but several others ran, possibly into a canal choked with reeds. So the Marines did something I found startling: it's a tactic called "recon by fire."

They aim their weapons into the canal and start shooting.

The logic behind recon by fire: it's better to fire a bullet blindly than send a Marine into harm's way.

But sometimes, Marine bullets hit innocent Iraqis. Last year, I filed requests for Marine Corps reports on these kinds of incidents like these that occurred during the 2004-2005 deployment to Iraq.

In one, Marines attached to the battalion's parent unit shot and killed a six-year-old boy who they mistook for an enemy.

In another, a lance corporal says he fired a warning shot into the road in front of an oncoming van.

The bullet ricocheted into the vehicle and struck four of its occupants, the report says, killing two. None of the reports contained direct testimony from Iraqis.

Marines from BLT one-two described other such incidents to me, but the corps did not release reports on them.

In that "recon by fire," Marines killed one more suspected insurgent in the canal. They detained two other men and a 16-year-old boy.

Staff sergeant Marino considered the day a success. He had brought his platoon and its Iraqi partners out alive.

MARINO: Everybody walked out of there without a scratch. You know? And we turned around and had four enemy kills, three persons under control. You can't ask for a better day. It was a really good day.

PALMER: Insurgents aren't the only Iraqis dying here. These police officers from the city of Iskandiriyah were killed last year by fighters opposed to their work with the Americans.

But most of the dying is done by civilians. Conservative estimates put the number of iraqi civilians killed since the 2003 invasion at more than 30,000.

After 60 days, BLT one-two rotated out, turning over the city of Hit to an Army unit almost overnight. The enlisted Marines had less than a day to brief soldiers taking their place.

MARINE: We got shot at by a sniper at this intersection right here...

SOLDIER: Is it the same guy? Or do you know?

MARINE: We think so... had a grenade thrown at us the other day up here on Aspen.

PALMER: Handovers like this happen periodically all over Iraq: one unit, in this case an army battalion, takes over from another.

The Marines will pass on the lessons they've learned here but the Army is under no obligation to use them.

Colonel Frank McKenzie is commander of Marine forces in the city of Hit.

MCKENZIE: The enduring problem we have, and what I think the biggest problem we have here in Iraq, is the short turnover between units. We were on the ground for about 60 days. We did a lot of great things but I am concerned that the largest single lesson people will draw from it will be the fact that we left at the end of 60 days.

The handover was the moment the insurgents were waiting for. They struck hard, launching a full-on attack against the new army unit with small arms and rocket-propelled grenades.

The Marines got orders to head south to Kuwait and, eventually, home.

PALMER: But not all the Marines are going home. Three members of Charlie Company were killed by an IED in February. They were the BLT's only deaths during the 2006 tour in Iraq.

Marines make up about 18% of the 133,000 U.S. troops now deployed in Iraq.

The Marine Corps is a much smaller force than the Army, but it sends a greater percentage of its troops into combat, so the proportion of Marine casualties is higher: almost 30% of U.S. military deaths since the invasion have been Marines.

BROUSSARD: We would get off of post frozen, toes so cold we could barely walk down the stairs. And we would sit in front of the heater and talk about our plans for when we got home, plans that he will never have the chance to fulfill.

PALMER: As the war in Iraq enters its fourth year, America's armed forces are stretched to the limit.

MCKENZIE: I think it's safe to say that any infantry battalion in the Marine corps is going to be coming into Iraq, at least in the near term.

Staff Sergeant Marino is pretty sure he'll be sent back to Iraq. He's making a career in the corps, and from his perspective, after two tours in Iraq, the BLT made progress.

MARINO: We are looking in the right direction through the elections, through way higher than Staff Sergeant Marino and his Marines, but the process is working, slowly but surely time well tell. It's gonna take time. You can't walk into a country and say, "Hey, this is the way it is, these are the rules, you gotta just play along..."

PALMER: But the continuing cycle of deployments is taking its toll. Lance Corporal Broussard also sees himself as a "lifer." When I was in Iraq last year, He was gung ho  "oorah" as the Marines say  about the mission. Not anymore.

BROUSSARD: I don't see any more good coming out of being here, you know what I'm saying? It's just... You can only make so much progress and then you have the guys hiding behind the scenes planting IED's and stuff, and it's so hard to stop that, you know what I'm saying? It's like, I don't know, you can only do so much until you friggin' slam your face into the wall so many times.

BRANCACCIO: Iraq isn't the only place where American troops are providing the muscle for an attempt at nation-building.

Last year, 98 Americans died trying to win the peace in Afghanistan.

The NATION magazine's frequent contributor Christian Parenti just spent a month in Afghanistan, where both the Taliban and the warlords are on the rise again.

BRANCACCIO: Christian, good to see you.

PARENTI: Good to see you, too.

BRANCACCIO: So you've been with Afghan farmers every day, Afghans... U.S. soldiers, European soldiers, even it sounds like, a senior western spy. Where are things headed in that country?

PARENTI: It seems that things are not going very well in Afghanistan. The U.S. has cut its commitment in terms of troops and development aid, and the Europeans are increasing theirs. But the security situation is deteriorating. The Taliban attacks are up, U.S. casualties are up. Last year, Afghanistan was as dangerous for U.S. troops as Iraq was.

And the nature of Taliban attacks is changing. They're using suicide bombings a lot more. And they're attacking civilians, which they hadn't done in the past. So things are not good.

BRANCACCIO: As dangerous as Iraq, what's that? There's not as many people, not as many U.S. soldiers who died. But if you do what the rate, the ratio..

PARENTI: The rate is the same, even though there's far fewer U.S. soldiers in Afghanistan.

BRANCACCIO: Now, you mention the Taliban. You actually met a bunch of these guys what, on a lonely road?

PARENTI: In a canyon not far from Kandahar in Zabul province. Just off the road, the main road between Kabul and Kandahar, my translator and I managed to hook up with a group of Taliban fighters. The Taliban mostly operate in groups of five or six, and then they come together maybe up to 50 fighters at a time, to do stuff like they did the other day, attack a U.S. base. And they're pretty clearly... according to these guys and then a Taliban spokesperson I spoke with, this western spy, and some Afghan intelligence people, the Taliban is run out of Pakistan with the support of the Pakistani state. They have sort of three main fronts that they operate out of. And they're a coherent, aggressive movement wreaking havoc with the aid of a U.S. ally, Pakistan. And the Bush Administration seems to be putting no pressure on Pakistan to change that policy.

BRANCACCIO: So you have the insurgency, the Taliban. Who really holds the actual power within Afghanistan at this stage?

PARENTI: You know, there is no one group that holds power within that country. Because the country is so broken up into a series of fiefdoms. And local powers are sort of city states around the major cities like Herat or Kandahar. But the government, Karzai's government, is populated by very horrible warlords with abominable human rights records.

And the main problem is that George Bush has used Afghanistan as a prop in his domestic political theater and rushed through the creation of the government there. And so there is now a government made up of really horrible criminal warlords.

One of the people that I interviewed, one of the stories I did out of this trip was with a former Taliban commander who was responsible for the destruction of the Buddhas in Bamiyan; those ancient statues. He's now in the Parliament. That's just one example. You could go on and on.

Those types of people, once in government, turned the ministries and the agencies they control into patronage organizations. They have, even according to the Afghan government, involved in drug running. So you have a government that is incapable of delivering development. And basically just becomes a nepotistic patronage system that's riddled with corruption.

And then in the countryside the local warlords, the big landlords, the leading families control their areas. The independent human rights commission in Afghanistan located and actually managed to close 40 different private detention facilities. But there are many more. So there is no one power. There's just localized power. And in the South, the Taliban are increasing in power.

They've burnt and closed 200 schools this year. They stop traffic and tax it on the roads. They operate with relative impunity. And actually with the support of the very sort of conservative Pashtun villages in the South.

BRANCACCIO: Now if you look at benchmarks for success or failure in that country, the security situation probably paramount, but a lot of people would want to know, in general, are they educating kids? What is the role of women so oppressed under the previous Taliban regime. What is the role of women now?

PARENTI: There has been some improvements. I mean for... it's a mixed bag. There are many women in the Afghan parliament. Many more then people thought would win in the election. There have been roads paved. There have been efforts to build schools.

$8 billion has been spent over the last four years. But the World Bank has called corruption in the aid sector and development sector sky high. The director there has said this is the worst he's ever seen in his 30 year career. But nonetheless some money has hit the ground. But the main problem is that those efforts, when successful, are now being undermined by the war.

And by the rise of Taliban terrorism. So that the insecurity in the villages means that people are afraid to send their children to or their daughters in particular to school. So it's a different picture between, you know, looking at the demographics of the parliament in Kabul. And real life in the villages is deteriorating badly.

BRANCACCIO: All right. Christian Parenti, contributor to The Nation magazine, thank you very much.

PARENTI: Thank you.

BRANCACCIO: You can learn more about Afghanistan, Iraq, our troops and the real story over there at pbs.org.